.button {
  position: relative;
  appearance: none;
  background: #337ab7;
  // padding: 1em 2em;
  padding: 10px 20px;
  border: none;
  color: white;
  // font-size: 1.2em;
  cursor: pointer;
  outline: none;
  overflow: hidden;
  border-radius: 10px;
 
  text-align: center;
  width: 180px;
  height: 40px;
  line-height: 20px;
  box-sizing: border-box;
  box-shadow: inset 0 -2px 0 #23527c;
  margin: 20px auto 40px;

  transform: scale(2);
  span {
    position: relative;

    letter-spacing:8px
  }
 
  &::before {
    --size: 0;  
 
    content: '';
    position: absolute;
    left: var(--x);
    top: var(--y);
    width: var(--size);
    height: var(--size);
    background: radial-gradient(circle closest-side, #4405f7, transparent);
    transform: translate(-50%, -50%);
    transition: width .2s ease, height .2s ease;
  }
 
  &:hover::before {
    --size: 400px;
  }
}
